Closure with safety feature

ABSTRACT

Disclosed is a closure for a container wherein the container may experience an excessive buildup of internal pressure. The closure is equipped with a “blowout” portion which partially separates from the remaining closure portion if internal pressure exceeds a predetermined limit. The separation occurs at a line of weakness. The line of weakness is specially designed to withstand external, incidental pressure resulting from normal handling yet fracture in a controlled fashion should internal pressure exceed a predetermined amount. In this way inconvenience and possible hazard is avoided from a closure completely separating from the container from excessive pressure.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional Application61/021,933 filed Jan. 18, 2008.

FIELD OF THE INVENTION

The present invention relates to a closure for containers and toclosures in combination with neck structures, and in particular toclosures suitable for applications that require safeguard againstaccidental displacement of closures as resulting from excessive internalpressure within the container void or head space, such as the closurebeing propelled, or acting as a projectile, away from the container.

BACKGROUND ART

In recent years with the increase in non-carbonated beverages and stillwater drinks, the use of flat closures with mechanical sealing featureshas become commonplace.

Since the containers do not contain carbonation, inert gas is often“dropped” into the containers to maintain stability. The containersinclude inert gas with internal pressures up to 2 bar(g). Inert gas isused because it limits the ingress of external gases preventing thecontainer from collapsing and assures product life. The inert gasfurther provides for a cost effective environmentally acceptablepackage.

When the containers can be filled under sterile conditions an asepticcontainer is created. The aseptic container, when correctly sealed,provides an extension of the product's shelf life without the need toadd preservatives or inhibitors to the product. In other cases, freshfood products lacking preservatives may be packaged under non-asepticconditions but maintain their integrity for some period, often underrefrigerated conditions. However, if the defined shelf life conditionsare violated through improper stock rotation or refrigeration, productspoilage may lead to closure blow-off or “missiling”. Such unintendedclosure displacement is clearly both inconvenient and potentiallyhazardous.

Conventionally, the closure is constituted by a main body comprising askirt or neck ring, of various diameters, which must be applied onto theneck of a container. In most cases the skirt or neck ring is threadedalthough this is not a requirement. Plug or snap fitting closures mayalso be considered. A sealing device attached to the inner face of theclosure suitably comes into contact the upper face or inner wall of theneck to form a seal.

The main body of the closure is normally initially screwed onto the neckof the container. However, in the case of familiar snap-on/screw-off orsnap-on/snap-off closures, initial application may be achieved with astraightforward axially directed push.

As a guarantee of the integrity of the container, the container can beprovided with a form of tamper evidencing means well known in the art.The means include breakaway bands, tear tabs and the like which separatefrom the main closure body on initial removal of the closure from thecontainer neck.

The above-described closures normally effectively perform their primaryintended task. However, on occasion they suffer the drawback that theintegrity of seal is so effective pressure is able to build up as aresult of, for example, product reaction (fermentation) or increase ingaseous pressure within the contained void this as a result of expansiondue to temperature or overfilling.

This drawback has been dealt with typically, by installing a mechanismto assist the release (venting) of excessive pressure past the sealingmechanism(s) to atmosphere by permitting passage of said gas or productbetween the closure and neck finish. An example of such a device isdisclosed within U.S. Pat. No. 7,314,146, the entire contents of whichare herein incorporated by reference. Unfortunately, such currentventing systems occasionally plug either through evaporation or withsolid ingredients, such as pulp, which may be present in the product.Any such plugging thwarts the effectiveness of the intended ventingmechanism.

DISCLOSURE OF INVENTION

The present invention thus includes an embodiment to provide a closurefor containers of liquids which solves some or all of theabove-mentioned drawbacks.

An embodiment of the present invention further provides for a closurethat can be easily sterilized internally with sanitizing liquidaccording to known methods. An embodiment of the present inventionfurther provides for a closure that is able to operate with pressuresgreater than 0.5 bar(g) and less than that associated with carbonatedproducts of the order of 3 bar(g) without leakage or premature openingof the upper closure.

A further embodiment of the present invention further provides for aclosure that allows repeated opening and re-closing.

Yet another embodiment of the present invention provides for a closurethat is able to give the user assurance, at the time of purchase, of theintegrity of the container, such that the user is certain that thecontainer has never been opened before.

Another embodiment of the present invention further provides for aclosure that can be manufactured at a cost, which is appropriate forsingle use applications.

Another embodiment of the present invention provides a breakaway shapeddisc located within the sealed area of the closure preferably though notnecessarily in the portion forming the upper section of package. (roofof cap)

A further embodiment of the present invention provides a disc with afrangible connection able to displace more easily in an outwarddirection as compared to inwardly in the event of excessive internalpressure thereby avoiding incidental puncture during consumer handling.

A further embodiment of the present invention is that the breakaway discshould be larger than the depending opening along sufficient land so asto inhibit accidental breakage of said frangible connection in adownward direction.

A further embodiment of the present invention is that the frangibleconnection should be interrupted in form adequately to maintainattachment of a breakaway disc to the primary closure thus avoidingchoking risk and full dislodgement of the disc.

A further embodiment of the present invention is that frangible line canbe so formed in the top face so as to create a pleasing shape in theform of a decorative logo or wording.

A further embodiment of the present invention is that the frangible linedefining a breakaway portion is able to be tapered or graduated in form,thereby allowing gradual and increasing breakage as pressure increasesand limiting the risk of product plugging.

A further embodiment of the present invention is that the invention canbe used in aseptically clean packages without risk to the standard packseal integrity.

A further embodiment of the present invention is that is can be used inconjunction with primary venting mechanisms and in this case of use actonly as a final safeguard against entire blow-off of the closure fromthe neck finish.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings which are incorporated in and form a part ofthe specification illustrate preferred embodiments of the presentinvention and, together with the description, serve to explain theprinciples of the invention. In the drawings:

FIG. 1 is a side elevational view in section of an embodiment of theinstant invention;

FIG. 2 is an exploded view of the closure portion encircled within thecircle identified as “A” in FIG. 1;

FIG. 3 is a sectional view of the structure of a conventional prior arttear line;

FIG. 4 is a perspective view from the top of an embodiment of theinstant invention; and

FIG. 5 is a top plan view of the closure of FIG. 4.

DESCRIPTION OF THE EMBODIMENTS

The aspects of the instant invention will now be described in detail inconjunction with the descriptive figures. While the invention issusceptible to embodiments in many different forms, there are shown inthe drawings and will be described herein, in detail, the preferredembodiments of the present invention. It should be understood, however,that the present disclosure is to be considered an exemplification ofthe principles of the invention and is not intended to limit the spiritor scope of the invention and/or the embodiments illustrated.

Referring now to FIG. 1, there is shown a side elevational view insection of a closure identified by numeral 10. Closure 10 comprises atop or “roof” 12 having a generally circular shape. Closure 10 furthercomprises a skirt or “neck ring” 14 depending from the peripheral edgeof top 12. As best seen in FIG. 4, skirt conventionally is ofcylindrical form although this form is not a requirement of the instantinvention.

Skirt 14 has an internal surface 16 and external surface 18. In theembodiment, a pattern of gripping knurls 20 is positioned on externalsurface 18. Knurls 20 assure facile manipulation of closure 10 by theconsumer and further facilitate rotary application of threaded closures.Closure 10 is further characterized as having container engagementstructure 22 positioned on the internal surface 16 of skirt 14. In theembodiment, engagement structure 22 comprises internal helical threads24. As is known in the art, threads 24 are complimentary to externalthreads (not shown) positioned of the external surface of a suitableneck finish (not shown) of a container. The internal threads 24 andmating external neck threads interengage to achieve secure and facileapplication, removal, and reapplication of the closure 10 relative thecontainer. As is known in the art, other disengageable features such assnap beads may often be substituted for the complimentary threadstructure of the embodiment.

Depending from closure top 12 is seal plug or valve 26. As is known inthe art, plug 26 is in the form of a hollow cylinder depending from thebottom surface 28 of top 12. Plug 26 normally has a smooth, seamlessexternal surface 30 which is intended to seal against an internalsurface of a container neck (not shown).

Depending from the lower edge of skirt 14 is a tamper evidencing band32. Band 32 is conventionally in the form of a cylinder joined to theprimary closure skirt 14 through a frangible line of weakness 34.Internal locking structure 36 projects radially inwardly from aninternal surface of band 32. Locking structure 36 may take many forms asis known in the art. The function of locking structure 36 is tointerengage with complimentary external locking structure on a neckfinish. The engagement restricts upward movement of the band 32 duringinitial closure removal from the container and the band separates fromthe main closure at the line of weakness 34 during initial closureremoval.

In the embodiment of the instant invention shown in FIGS. 1, 2, 4 and 5,the closure top 12 comprises a “breakaway” portion 38 joined to anannular peripheral portion 40 through a line of weakness 42. In theembodiment shown, the portion 38 has a disk-like shape. Many othershapes are possible within the scope of the invention. For example, theshape of the “breakaway” portions may be provided within embossingfeatures. Other geometrical shapes in the form of a logo or otherdecorative designs are possible. The possibility of this myriad ofalternative “breakaway shapes” will be clear in light of the instantteachings. In the embodiment shown, the line of weakness 42 does notextend for a complete circle. Thus the breakaway portion 38 defined bythe line of weakness 42 will not completely separate from the package topose a potential hazard.

The structure of the top frangible line 42 is best seen in FIG. 2, agreatly exploded view of the encircled portion identified as “A” inFIG. 1. In FIG. 2, it is seen that the line of weakness 42 in theembodiment is formed by overlap of extending portion 44 of breakawayportion 38 and extending portion 46 of peripheral portion 40. Theoverlapping region, generally identified by numeral 48, forms a line ofweakness 42 joining top portions 38 and 40. Forming the frangible lineof weakness 42 in this way achieves a number of important advantages.First, it mitigates the possibility of accidental rupture of the line ofweakness due to inadvertent pressure being applied from the exterior ofthe container. This is because the frangible line 42 fails in tensionrather than compression. Inadvertent exterior pressure, generallyindicated by the arrow 50 in FIG. 2, would naturally be appliedprimarily to the central blowout disk portion 38 of top 12, placing thefrangible overlap region 48 in compression. A tensile failure caused byinadvertent external pressure applied to the peripheral portion 40 isprevented by the reinforcing structure present from the plug 26 andcontainer neck finish. On the other hand, pressure from inside thecontainer is exerted primarily over the surface area of the breakaway orblowout disk, thereby placing the frangible line in tension. As can beseen from the sectional view shown in FIG. 3, a conventional tear lineformed using a thin score line is essentially unable to discriminatebetween external and internal pressure since the tear line is placed intension in either case.

Another important aspect, of the structural geometry of frangible tearline 42 is that the actual strength of the tear line can be easilyvaried at any point along its length. This variable strength aspect iseasily achieved by simply varying the width of the overlapping region48. For example, a graduated tear line strength allows a gradual butpredetermined release of any excessive internal pressure therebypreventing explosive pressure release.

The tear line structure embodied in FIG. 2 is achieved by overlap ofextending portions 44 and 46 which are shown to be thinner thanimmediately adjacent portions 38 and 40 respectively. This structuralarrangement allows the closure top to maintain a substantially constantthickness except for the region occupied by the tear line. Thischaracteristic is important should secondary operations such as slittingto form frangible line 34 be employed.

Finally, the tear line structure of FIG. 2 is characterized by smoothaccessible surfaces to allow facile sterilization for aseptic packaging.

1. A closure having a top sized to cover and seal a container orifice,wherein said top comprises a pressure relief portion, said pressurerelief portion joined to the remainder of said top through a frangibleline of weakness.
 2. A closure as in claim 1 wherein said line ofweakness is designed to resist external pressure on said pressure reliefportion and to fracture in a controlled fashion in response to pressureon said pressure relief portion exceeding a predetermined value.
 3. Aclosure as in claim 2 wherein said line of weakness varies in strengthalong its length.
 4. A closure having a top and a skirt depending from aperipheral edge of the top and further comprising a breakaway portionjoined by a line of weakness to an annular peripheral portion defined onthe top, wherein the breakaway portion includes a first extendingportion extending towards the annular peripheral portion and wherein theannular peripheral portion includes a second extending portion extendingtowards the breakaway portion, the first and second extending portionsoverlapping to define an overlapping region.
 5. The closure of claim 4further comprising: a seal plug depending from a bottom surface of thetop, the seal plug shaped to form a hollow cylinder and having a smoothexternal surface intended to seal against an internal surface of acontainer neck.
 6. The closure of claim 5, wherein the first extendingportion of the breakaway portion overlaps on top of the second extendingportion of the annular peripheral portion, wherein pressure applieddownwards on the top causes the seal plug to press against the internalsurface of a container neck placing the overlapping region incompression an insufficient force for tearing the line of weakness,whereas pressure applied upwards on the bottom surface places theoverlapping region in tension such that the line of weakness is capableof tearing.
 7. The closure of claim 4, wherein the breakaway portion hasa disk shape.
 8. The closure of claim 4, wherein the line of weaknessextends as an arcuate line of weakness.
 9. The closure of claim 4,wherein the line of weakness extends in an arc less than 360 degrees.10. A closure having a top, a skirt depending from a peripheral edge ofthe top, and a seal plug depending from a bottom surface of the top, theseal plug shaped to form a hollow cylinder and having a smooth externalsurface intended to seal against an internal surface of a containerneck, the closure further comprising: a breakaway portion joined by aline of weakness to an annular peripheral portion defined on the top,wherein the breakaway portion includes a first extending portionextending towards the annular peripheral portion and wherein the annularperipheral portion includes a second extending portion extending towardsthe breakaway portion, the first and second extending portionsoverlapping to define an overlapping region, and wherein the firstextending portion of the breakaway portion overlaps on top of the secondextending portion of the annular peripheral portion, wherein pressureapplied downwards on the top causes the seal plug to press against theinternal surface of a container neck placing the overlapping region incompression an insufficient force for tearing the line of weakness,whereas pressure applied upwards on the bottom surface places theoverlapping region in tension such that the line of weakness is capableof tearing.
 11. The closure of claim 10, wherein the line of weaknessextends as an arcuate line of weakness.